New female-controlled products are urgently needed for HIV prevention and intravaginal rings (IVRs) that release antiretroviral drugs such as dapivirine (DPV) are one technology being developed. Two phase III trials of a monthly DPV ring are underway and expect to report efficacy results in late 2015 and early 2016.
We modeled the introduction of the DPV ring in South Africa from 2017, assuming a range of efficacy estimates (25%, 50%, 75%). The intervention was highly prioritized to high-risk women (30% coverage among sex workers and 10% among other women with multiple sexual partners) and introduced under different assumptions about the counterfactual scenario: (1) current levels of existing HIV prevention methods (condom use, male circumcision, early ART) are maintained over time; (2) existing prevention methods increase over time; (3) as (2) with the addition of oral PrEP. We assumed a one-off fixed cost of 10 million USD for the introduction of the DPV ring plus 5 million USD per year for mass media. The variable cost ranged from 107-115 USD per person per year depending on the population sub-group, and we assume that prevention and treatment interventions call on the same overall ‘HIV budget’. We estimated the health impact and cost-effectiveness of the DPV ring relative to the three counterfactual scenarios per disability adjusted life year (DALY) averted. All costs are discounted at 3% per year.
The DPV ring could avert 125-175 thousand, 265-364 thousand or 427-588 thousand infections at 25%, 50% and 75% efficacy, respectively, from 2017-2050 under the different counterfactual scenarios. This represents 1.1-1.9%, 2.5-4.2% and 4.0-7.0% of total HIV infections in this period at corresponding cost-effectiveness of 1000-1300, 370-520 and 160-260 USD per DALY averted (Figure 1). All cost-effectiveness estimates are below 25% of South African GDP per capita.
The DPV ring could substantially and cost-effectively generate health among women in South Africa even under the lowest efficacy estimates, provided it can be successfully prioritised to those at greatest risk. However cost-effectiveness does not necessarily imply the intervention is affordable and in other settings the ring my be less likely to be cost-effective. The success of the DPV ring will also be determined by user demand and adherence, and new and forthcoming data on women’s preferences will be critical for determining its use across different settings.